Many devices for holding a poisonous bait to control crawling insects are known, ranging from simple cardboard tubes open at both ends with the bait glued inside to more elaborate structures that have a centrally enclosed bait accessible by peripheral openings.
Early insect traps, as stated, lacked features to prevent access to the poisoned bait. Examples are U.S. Pat. No. 1,372,780, which discloses a bellshaped top having side apertures, which fits over and clamps to a dish shaped base, and U.S. Pat. No. 2,123,995, which discloses a flat piece of sheetmetal which is bent over an insecticidal substance to partially cover the substance while allowing insects direct access.
U.S. Pat. No. 4,563,836 to Woodruff et al. discloses an insect feeding station comprised of a simple cover which fits over a base, the base having external wall segments with entrance gaps between them and interior walls placed opposite the gaps and surrounding a central bait area. The outer walls of the present invention are formed by the cover; the entrance apertures are oriented at an angle to the required line of approach to the bait, and a ramped structure surrounds the bait well.
U.S. Pat. Nos. 278,032 and 278,842 discloses designs for insect feeding stations, simliar to those of the '836 patent, having a cover over a base with baffle means.
Pending U.K. patent application No. GB2128463A, discloses an insect feeding station having an aperture-containing cover placed over a base, the base having baffle means for directing an insect toward the central bait section. There is no teaching of a central ramp structure surrounding a bait well.
Pending U.S. patent application Ser. No. 07/069,338 to Demarest et al. discloses an insect bait device which has two substantially identical housing portions which are joined together to enclose an insecticide, the two housing portions together forming access apertures for insects. The possibility of multiple unit array manufacture is disclosed.
There are three main features that are desirable in such a trap:
the bait containing area must securely hold the bait so that no bait can become dislodged from the device;
the bait should be inaccessible even should a child attempt to probe the device with a stick or other object;
the device should be so constructed that insects have easy access to the bait.
Obviously these features are somewhat opposed, i.e., the structure allowing the most direct access for insects would also allow an animal or a curious child access to the poison.
Another desirable feature would be a device that would be easy and inexpensive to manufacture.
Thus, it is an object of the present invention to provide a bait station that provides a secure location for the bait that is inaccessible to children or animals.
It is also an object of the invention to provide a bait station that allows insects easy access to the bait.
It is a further object of the invention to provide a bait station that can be easily and cheaply manufactured.